The invention relates to a ski with improved profile, as is particularly intended for the practice of winter sports, and more particularly for alpine skiing.
As is known, skis consist of a running sole, intended to be in direct contact with the snow or ice, and whose lateral borders are fitted with metal edges, themselves connected to the upper face of the ski by lateral portions termed side walls. The side walls maybe vertical or inclined.
Traditionally, skis are thicker at the support face than at the ends where the ski progressively thins. This greatest thickness is intended on the one hand to allow mounting of the screws of the bindings which hold the shoes of the skier, and on the other hand, and above all, to give this central zone increased rigidity, in order to allow sufficiently widespread distribution of the load induced by the mass of the skier.
Furthermore, in order to give the ski qualities of speed and qualities of response, it is important for its two ends to be relatively flexible and thin.
A ski has for example been proposed in document FR-A-2,664,172 (SALOMON) in which, on the one hand, the zone of the support face has a central rib intended, with adapted shoes, to allow the foot of the user to be brought closer to the edges, in order to improve the effectiveness of setting the edges and, on the other hand, the forward and back zones of the ski, with respect to the central support surface, were lowered at the mid part and raised on the borders in the form of lateral ribs. In this way, it is possible to obtain flexibility of the ends, while preserving the inertial masses improving the dynamic behavior of the ski.
Nevertheless, although it is true that through this procedure the resulting ski has sufficient inertia in its zones uphill and downhill with respect to the support zone, while thereby giving the ski greater flexibility, and, thereby promoting bending of the ski and therefore rounding of the turn, on the other hand, such a configuration is observed to cause a loss in rigidity of the ski, in particular in twisting, which results from bringing the reinforcement elements of the neutral axis of the ski closer to the forward and backward zones. Now, this decreased rigidity produces on the one hand relative weakness of the ski, which can even lead to risks of breakage, and on the other hand the onset of vibrations, with a significant detrimental effect on the behavior of the ski on the snow, in particular making it more difficult to hold the ski in the desired direction. Furthermore, a ski with this configuration requires either the use of specific shoes, including a wide central groove allowing the central rib of the ski to be accommodated, or the use of specific binding plates which are compatible with the presence of the central rib of the ski.
Decreasing the mass of skis currently constitutes an area of great interest to manufacturers, because a ski which is too heavy may hinder the user. In fact, such a ski is difficult to direct, is difficult to handle and gives the skier the impression of being stuck to the snow. In contrast, ends which are too light can generate other undesirable sensations during use, and in particular give the impression that the tips are unsteady, through a lack of steering effect, which can be exhibited by inaccuracies in following a line.